A touch input device is a user interface where a user can input user operations simply and intuitively by touching a display surface or a designated touch surface with a finger, an electronic pen, or the like. Touch input devices may be applied to various technical fields, such as navigation devices, telematics terminals, personal digital assistants (PDAs), laptop computers, notebook computers, smartphones, and others.
Touch input devices use a variety of touch sensing technologies including resistive overlay, capacitive overlay, surface acoustic wave (SAW), and infrared beam. Conventional touch sensing technologies may sense touch coordinates, i.e., X-axis and Y-axis coordinates on the flat surface of a panel, and thus, they may be limited to two-dimensional (2D) touch interaction.
In order to overcome the limit of conventional 2D touch interaction, a force-based touch sensing technology (three-dimensional (3D) touch interaction) that senses the force of a touch using a force sensor together with touch coordinates has been proposed.
Furthermore, a conventional touch input device has a plurality of force sensors attached to the bottom surface of a touch panel. When a touch is applied to the touch panel, the sensors are used for various purposes, such as sensing the position, intensity, and the like of the touch.
A conventional touch input device is only capable of sensing a touch in an area inside a virtually connected border by the plurality of force sensors attached to the bottom of end edges of the touch panel, however, and is not capable of sensing a touch in an area outside of the border. That is, when the force sensors are attached to the end edges of the touch panel, the touch sensing area may be narrowed.
In particular, when the touch input device is applied to various apparatuses, various curved surface structures, various conditions, and the like, it may be difficult to expand the touch sensing area.